4Ez!I TNMJT,: Indian Standard

Free Standard provided by BIS via BSB Edge Private Limited to Galaxy Test & (Reaffirmed
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IS 15707:2006
(Reaffirmed 2012)
Wv5%7m (Reaffirmed 2016)

(Reaffirmed 2011)
4EZ!Im TNmJT,
“q@iwr,
(Reaffirmed 2015)

T5F?@m — a-fa +-R-al

(Reaffirmed 2010)
(Reaffirmed 2014)

Indian Standard

(Reaffirmed 2009)
TESTING, EVALUATION, INSTALLATION AND
(Reaffirmed 2013)
MAINTENANCE OF ac ELECTRICITY METERS —
CODE OF PRACTICE
(Reaffirmed 2008)
(Reaffirmed 2012)

(Reaffirmed 2007)
ICS 17.220.20
(Reaffirmed 2011)

(Reaffirmed 2006)
(Reaffirmed 2010)

(Reaffirmed 2005)
(Reaffirmed 2009)

(Reaffirmed 2008)
(Reaffirmed 2007)
(Reaffirmed 2006)
(Reaffirmed 2005)
Q BIS 2006
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
November 2006 Price Group 8

Free Standard provided by BIS via BSB Edge Private Limited to Galaxy Test & Calibration Lab -
Equipment for Electrical Energy Measurement and Load Control Sectional Committee, ET 13
FOREWORD
This Code was adopted by the Bureau of Indian Standards, after the draft finalized by the Equipment for Electrical
Energy Measurement and Load Control Sectional Committee had been approved by the Electrotechnical Division
Council.
Though tlm-e are Indian Standards on electricity metering, need was felt for comprehensive information on the
best practices in order to provide guidance to various stakeholders and electricity service providers responsible
for not only testing, evaluation and installation of ac electricity meters at site, but also for maintenance of their
metrological and functional performance. This Indian Standard in the form of a ‘Code of Practice’ addresses these
issu~s. The objective of this Code is also to establish a performance based good meter asset management plan.
During the useful life of an electricity meter in open market, the following four categories of stakeholders have
their specific roles to play in managing dependability of meter asset:
a) Electricity consumers — set requirement targets;

b) Meter manufacturers — provide desigtireliability and metrological reports/data;
c) Notl>ed bodies — approve design, assign useful life, monitor quality, and set regulations; and
d) Metering service providers — from purchase to disposal, through installation, removal and repair, with
test ing and calibration, optimally meet consumers’ target at the centre stage of dependability management
of meter asset within economical, regulatory and availability constraints.
In the background of this partnership based dependability management of meter asset, model recommendations
for in-service compliance practices have been framed for protection of interest of the parties — consumers,
electrical energy providers and metering service providers, but economical viability will depend on overall
effectiveness of dependability regime.
This Code is applicable for both static and electromechanical meters. The considerations based on reliability
prediction or accelerated reliability testing for assignment of useful life, are also applicable fix both types of
meters.
In case of any contradiction between a normative requirement of this Code and the Central Electricity Authority
(Installation and Operation of Meters) Regulations under the Electricity Act, 2003, the requirement(s) of the
regulations shall be decisive and binding. The corresponding clause(s) of this-Code will then be treated as informative
for good practices along with other informative clauses earmarked in the scope.
For the purpose of deciding whether a particular requirement of this standard is complied with, the final value,
observed or calculated expressing the result of a test or analysis, shall be rounded off in accordance
with IS 2: 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in
the rounded off value should be the same as that of the specified value in this standard.
IS 15707:2006
Indian Standard
TESTING, EVALUATION, INSTALLATION AND
MAINTENANCE OF ac ELECTRICITY METERS —
CODE OF PRACTICE
1 SCOPE a) Correct and proper installations;

b) In-service surveillance; -
1.1 This Code outlines informative requirements and
good guidance as Code of practices to various c) Safety measures;
stakeholders and service providers in metering industry d) Testing at various stages;
responsible for maintaining metrological and e) Standards for meter testing and periodicity of
functional performance throughout the long unattended calibration thereofi
period of useti.d life of.ac electricity meters, covering -0 Concept of certified life;
their testing, evaluation, installation and maintenance. g) Requirements for in-service compliance
The objective is also to establish a performance based testing; and
good meter asset management plan. h) Performance based meter asset register.
NOTES
“1.2 This Code covers the following aspects:
1 The attributes method of sampling has been considered
a) Type approval; in this Code.
2 Special requirements for Class 0.2 S extra high voltage
b) Life certification;
meters have been excluded and will be considered later.
c) Verification; 3 Presently there is no designated notified body in India
d) Sealing and seal management; responsible for type approval, life certification or
verification sealing. Part of the verification function is
e) Acceptance; covered under the BIS Certification Marks Scheme. Once
f) Transportation; a body is notified for type approval, life certification and
verification sealing 4, 5, 6, 7 would become normative.
g) Storage;
4 The reference to Electromechanical meters in this
h) Installation and commissioning; Code is for meters already installed.
j) Maintaining in-service with emphasis on in- 1.6 _The following clauses of the Code are informative.
service compliance; and
4 Type approval;
k) Meter test station practices.
5 Life certification;
1.3 This Code also deals with: 6 Verification;
a) Identification and removal of defects in 7 Verification sealing;
reasonable time; 11.3.3 Installation of instrument transformers;
b) Repair; 11.6 Terminations; and
c) Re-certification and re-verification; and 14 Recertification/Re-verification/In-service
recompliance 14 (a) and 14 (b) only.
d) Disposal.
1.4 This Code covers Class 2.0, 1.0, 1.0 S and 0.5 S 2 REFERENCES
low, medium and high voltage meters rated up to 33 kV The following standards are necessary adjuncts to this
as per IS 13010, IS 13779 and IS 14697. In-service standard:
compliance testing of meters for low and medium
1S No. Title
voltage applications are generally carried out using
statistical sampling techniques; so that metering 732:1989 Code of practice for electrical
providers may identify appropriate action plans for wiring installations (third revision)
divergent meter populations. At present sampling by 2500 Sampling inspection procedures:
attributes has been preferred. High voltage meters may (Part 1): 2000/ Part 1 Attribute sampling plans
be subjected to 100 percent testing. 1S0 2859-11999 indexed by acceptable quality level
(AQL) for lot-by-lot inspection
1.5 The model recommendations and practices are (third revision)
given with special emphasis on:
1
1s 157U7 : ZUU6
1S No. Title definitions-shall apply, besides the definitions given

Current transformers: in the referenced standards:
2705
(Part 1): 1992 General requirements 3.1 Type Approval — The initial part of a conformity
(Part 2): 1992 Measuring current transformers assessment procedure whereby a notified body
Code of practice for earthing (&t examines themselves or with the aid of an established
3043:1987
revision) meter testing laboratory, the technical design of a
prototype meter and” ensures and declares that the
3156 Voltage transformers:
technical design denoted by the approved type meets
(Part l): 1992 General requirements (second with the requirements of the relevant standard(s).
revision)
Measuring voltage transformers 3.2 Verification — The part of a conformity
(Part 2): 1992
(secondrevision) assessment procedure whereby a notified body ensures
continuously or periodically the conformity of the
3961 Recommended current ratings for
production batches of meters to the approved type.
cables:
(Part 1): 967 Paper insulated lead sheathed 3.3 Reference Standard — A standard whose
cables measurement traceability has been verified at an
(Part 2): 967 PVC insulated and PVC sheathed accredited laboratory and is used for in-house verification
heavy duty cables of other standards in the meter test station (M. T.S.).
(Part 3): 968 Rubber insulated cables 3.4 Transfer Standard — acldc transfer standard and
(Part 5): 1968 PVC insulated light duty cables ac transfer standard of the meter test station (M. T.S.).
4146:1-983 Application guide for voltage 3.5 Working Standard — A standard including a
transformers ~rst revision) complete meter testing system, which has been verified
420”1:1983 Application guide for current by comparison to either a reference standard or a
transformers (fwst revision) transfer standard, and is used for calibration and testing
5547:1983 Application guide for capacitor of metering equipment.
voltage transformers @rst revision) 3.6 Mobile Standard — A standard, that is, ac transfer
8061:1976 Code of practice for design, standard or working standard, which is used for on-
installation and maintenance of site testing of metering equipment.
service lines up to and including
3.7 acldc Transfer Standard — A standard which
650 V
has been verified in comparison to .ac and also dc
11448:2000 Application guide for ac electricity
standards of an accredited laboratory. It is also
meters (ji-st revision)
periodically verified in-house against dc standards and
12346:1999 Testing equipment for ac electricity is used to verify ac transfer standards or working
energy meters (first revision) standards.
13010:2002 ac Watt-hour meters, class 0.5, 1 and
3.8 ac Transfer Standard — A standard which has
2 — Specification ~rst revision)
been verified by comparison to either a reference
13779:1999 ac Static watt-hour meters, class 1
standard or an acldc transfer standard, and is used for
and 2 — Specification (first
calibration and testing of metering equipment.
revision)
14697:1999 ac Static transformer operated 3.9 Certification — The part of a conformity
watt-hour and VAR-hour meters, assessment procedure whereby a notified body assigns
class 0.2S, 0.5S and 1.0S — and certifies the life of an approved type of meters.
Specification 3.10 Useful Life — The expected period in-service
14772:2005 General requirements for enclosures of an approved type of meter in compliance with the
for accessories for household and requirements -of relevant standards and certified by a
similar fixed electrical installations notified body prior to commencement of regular
— Specification ~rst revision) production. From the instantof initial installation, it is
lS/ISO/IEC 17025: General requirements for the extended up to the instant when failure becomes too
1999 competence of testing and calibration frequent so that repairing cannot be performed or it is
laboratories @st revision) economically not viable.
3 TERMINOLOGY NOTE — Unless the life is extended by the notified body

during use, the meters are taken out of service on expiry of
For the purpose of this standard, the following life. Similarly if the life be reduced by the notitied body during
2
IS 15707:2006
use, themeters aretaken outofservice onexpiryofmmlified specified criteria, to accept or reject a population is
tile
based on the inspection results obtained from a single
3.10.1 MinimumL(/e- Theminimumv alueofuseful sample of predetermined size and outlined in a specific
life for a particular category of meters set by a notified plan.
body for the purpose of certification and putting into
3.21 Error (of a Meter) — The registered value of
service of meters of an approved type belonging to that
energy (as indicated by a meter) minus the true value
category.
of energy in a specified time.
3.11 Reliability — The probability that a meter can NOTE — Since the true value cannot be determined, it is
maintain its metrological and functional capabilities as approximatedby a value with a stated uncertainty that can be
per relevant standards under given conditions of use traced to national standards.
for a given period. 3.22 Uncertainty — An estimate attached to a test
3.12 Dependability — The collective form of the result which characterizes the range .of values within
availability performance and its influencing factors: which the true value is expected to lie.
reliability performance, maintainability performance 3.23 Limits of Error — Values of error within which
and maintenance support performance. the metrological performance of a meter is required to
3.13 Durability — The ability of an item to perform be maintained or verified under reference conditions
a required function under given conditions of use and as specified by the relevant metering standards
maintenance, until a limiting state is reached. considering the measurement uncertainty of test results.
NOTE — A limiting state of an item may be characterized by 3.24 Maximum Error In-service — Maximum error
the end of the useful life, unsuitability for any economic or measured for a meter in service under rated operating
technological reasons or other relevant factors.
conditions.
3.14 In-service Compliance Period — The expected NOTE —.lt is related to error under reference conditions with
period in service of a particular population of meters uncertainties due to measurement and in-service shift under
in compliance with the requirements of relevant operating conditions as specified in relevant standards (the latter
part being calculated on root-mean-square-summation principle
standards and generally assigned statistically by
from specified variation of error due to individual influence
compliance inspection of the population. quantities),
NOTE — Initial compliance period may be gainfully used in
the absence of a certified life of meters, as part of a performance 3.25 Maximum Permissible Error In-service
based good asset management plan. (M.P.E.) — Extreme value of an error permitted by
this Code or national regulations for a given meter in
3.15 Population — A quantity of same type of in-
service under rated operating conditions as specified
service meters identified on the basis of similar
in relevant standards.
characteristics for the purposf of carrying out
compliance inspection as per this Code of practice by 3.26 Certification Sealing — The process ofaftlxing
adopting generally statistical techniques. distinctive seal(s) on a meter as a mark of verification
by a notified body and maintaining proper record for
3.16 Sample — Set of one or more items taken from a
traceability of the asset and the appliance with which
population and intended to provide information on the
sealing has been performed. The purpose of sealing is
population.
also to provide security to meter elements and the
3.17 Inspection by Attributes — Inspection whereby register.
the item under inspection is classified as conforming
3.27 Installation Sealing — The process of aflixing
or non-conforming with respect to a specified
distinctive seal(s) on a meter, metering equipment and
requirement(s).
installation with the intent of creating evidence of
3.18 Inspection by Variables — Inspection whereby unauthorized access to the metering systcm.
. .
~ Particular characteristic of each of the items under 3.28 Primary Packaging — The packaging that
Inspection is measured and recorded involving
immediately envelopes a product. It provides most of
reference to a continuous scale.
the strength and the moisture, vapour or grease barrier
3.19 Acceptable Quality Level (AQL) — The needed to safeguard the mete;’s per f&mance and
maximum percentage of defects of a given functionality from the time it leaves the suppliers site
characteristic in a population, which can be considered until its installation.
satisfactory for the purpose of sampling inspection.
3.29 Secondary Packaging —The outer package into
3.20 Single Sampling Inspection Plan — Sampling which the primary package is placed. Its major function
inspection in which the decision, according to a is to protect the meters during shipping and distribution.
3
IS 15707.:2006
3.30 Asset Register — A registration system, 4.2 Validity of Approval

electronic or otherwise, of metering assets ofa licensee
Generally the approvals shall be valid for a period of
recording various details related to theirprocurement,
10 years. For meters with certified life, it may continue
usage, ”status of in-service compliance, repair, reuse and
till the end of useful life.
“ disposal for the purpose of traceability.
3.31 Accredited Laboratory — The laboratory for 4.3 Amendment

maintaining electrical energy standards and In case of modification from the approved type, it will
accredited as per IS/IEC/ISO 17025 in a national/ be reported by the manufacturer and a fresh type
international calibration chain traceable to primary approval will be accorded on the basis of limited
S.1. standards. examination including limited type tests related to
modification(s). The extent of testing shall be as
4 TYPE APPROVAL
decided by the type approval authority.
4.0 The process of ascertaining the compliance of a
meter type as per the relevant standard by a notified 5 L-IFE CERTIFICATION
body is given below in brief. 5.0 Assigning a useful life to an approved type of
meters, usually by a notified body, is done on the basis
4.”1 Methodology
of one of the following.
4.1.1 The manner of type approval and the number of
prototype samples are generally determined by the 5.1 New Type of Meters
notified body. However, the samples are actually drawn a) By prediction of durability from estimated
and submitted by the manufacturer along with all reliability of components furnished by the
necessary documentation with details as given: manufacturer in the design stage; and
a) Type designation; b) By accelerated durability testing of the
b) Meter rating details; prototypes.
c) Drawing of nameplate; 5.2 Existing Type of Meters

d) Metrological characteristics, including:
a) By collection of reliability data from field;
1) Description of measuring principle;
b) By respecting removed meters from the field;
2) Metrological specification; and
3) Hardware adjustments, if any; and c) By sample survey of meters in service as part
e) Technical specification, including: of on-going compliance programmc.
1) Block diagram with fictional description NOTE — Removed meters from the field inspected for
of components and devices; the purpose of assigning useful life would not include
damaged or tampered meters.
2) Drawings, diagrams and general software
information explaining the construction; 6 VERIFICATION
3) Sealing arrangement and protective
The process of verification is to provide high level of
devices; and
confidence among users as well as the energy service
4) Data for dependability/durability providers.
characteristics for life estimation
(including possible software aspects in It covers the following objectives:
future). a) Maintenance of a quality management system
4.1.2 Type approval is accorded by the notified body by the manufacturer for meters of the approved
and a certificate is issued after: type with regular audit, and periodic
surveillance by a notified body;
a) Type tests are satisfactorily performed; b) Regular audit of meters awaiting dispatch
b) Type particulars as given m the documentation after manufacture for metrological
have been studied and recorded; verification to show conformity to the
c) Consistency of production feasibility has approved type on the basis of statistical
been examined and ensured based on sampling by attributes with AQL = 1, and
manufacturer’s report; and periodic surveillance of the manufacturer by
d) Minimum life has been ensured from a notified body;
dependability characteristics, which may be c) Periodic type testing on samples of the
10 years. manufacturer drawn by a notified body on the
4
IS 15707:2006
basis of a limited tests to prove conformity to The AQL for acceptance shall be 1.0 except for physical
the approved type; and verification, ac voltage test, insulation resistance test
d) Metrological verification of the meter test and test for meter constant, which shall be carried out
equipments (M. T.Es) of the manufacturer as as per AQL 0.15.
outlined in this Code. Acceptance of meters shall be carried out either on 100
NOTE — Bureau of Indian Standards (BIS) is operating percent inspection basis or on sample inspection basis,
B 1SCertification Marks Scheme in accordance with the as mutually agreed between supplier and purchaser. In
BIS ACI, 1986 and the Rules and Regulations made
thereunder, which covers the above objectives to some
case of inspection by sampling, it shall be carried out
extent. However, it is not the notilied body. as per double sampling plan as given in Table 3A read
in conjunction with Table 1 (for General inspection
7 VERIFICATION SEALING level II) of IS 2500 (Part 1).
7.1 One or more distinctive seal(s) are applied after The tests shall be as per the schedule of acceptance tests
production of a meter on behalf of the notified body as as specified in the relevant Indian Standards on metering,
an evidence of certification/verification. Seals are: namely IS 13010, IS 13779 and IS 14697. Any additional
test for physical and functional verification may be
a) Generally applied by authorized
carried out as mutually agreed to between the supplier
representatives of the notified body. Such
and the purchaser. Meter shall sealed by the manufacturer
representatives can be members of the
and shall be tested without breaking/opening
manufacturing company, but qualified by the
manufacturer’s distinctive (warranty) seal.
notified body;
NOTE — For simultaneous testing of sealed meters with internal
b) Made of metal ferule and stainless steel wire
potential links, multi secondary voltage transformers (MSVT)
to be affixed with a punch, plasticl or isolating voltage transformers (IVT)/isolating current
polycarbonate self-lock or adhesive sticker transformers (ICT) of appropriate accuracy class should be used.
with hologram;
8.2 Inspection Reporting
c) Provided with alphanumeric characters typical
of the manufacturer and a distinctive traceable The inspection observations report shall cover
number; comprehensive information on serial numbers of the
d) Approved manufacturer specific alpha Iot inspected, the lot size, the serial numbers of the
numeric characters are registered with the sample meters, the date of inspection and the name of
notified body; and the person inspecting. The report shall carry categorical
e) Traceable with documentation as may be statement of observations and results of the tests
necessary. mentioned in schedule of tests above. If any test is not
done or waived off, the same shall be mentioned along
8 ACCEPTANCE with the reason thereof.
8.1 The purchaser shall carry out acceptance of the The lot shall be cleared by the designated authority
meters offered for delivery by a supplier. The meters based on the inspection report. In case of non-
offered for acceptance shall be accompanied by test acceptance of the lot, the competent authority may take
results as per the routine test schedule of the relevant appropriate action.
metering standards duly signed by the manufacturer’s
9 PACKAGING AND TRANSPORTATION
quality assurance representative. The point of
acceptance of goods may be supplier’s premises, the 9.1 Packaging of Meters
buyer’s premises, or any other premises as mutually
The meters shall be packed appropriately to ensure safe
agreed to between the purchaser and the suppiier. This
transportation, handling, identification and storage of
usually depends on the commercial nature of the
meters from the manufacturer’s premise to the installation
contract, availability of appropriate acceptance testing
site. All packaging material shall be environment tilendly
facilities and logistics. In some cases, a staged
and in accordance with regulato~lenvironmental law or
acceptance process involving a pre-acceptance at
ruling. Use of non-recyclable material like polystyrene
supplier’s premise fo”llowed by a final acceptance at
(thermocol) should be avoided.
the purchaser’s premise may be adopted.
9.1.1 The primary packaging of meters shall ensure
The acceptance test procedure with be overseen and
protection against humidity, dust and grease and
certified by the purchaser’s representative. The
safeguard the meter’s performance and functionality
purchaser may choose to depute its own personnel, a
until-its installation.
third party or authorize the qualified personnel from
the supplier organization itself. 9.1.2 The secondary packaging of meters shall provide
5
IS 15707:2006
protection during shipping and distribution. The place. The storeroom chosen for such storage should
following shall be ensured: have proper ventilation and should be free from water
seepage, dust, vermin and corrosive gases. The meters
a) Meters shall be packed in suitable packaging
shall be stored on raised racks. Such racks should be
like corrugated cardboard cartons;
easily accessible or approachable by the users.
b) Number of meters in each cardboard carton
shall be determined by the convenience of Environmental conditions shall be maintained as given
handling; in Table 1,
c) Packing cases shall indicate the fragile nature
of the content and direction of placement of Table 1 Environmental Conditions for Storage
box. Each packaging shall clearly indicate the
S1 Influence Quantity Permissible Limits
marking details (for example, manufacturer’s No.
name, serial numbers of meters in thepackage, (1) (2) (3)
quantity of meters, other details as agreed, etc)
O Ambient temperature As per relevant Indian Standard
of the consignment as agreed between the
(see Note)
supplier and the purchaser; and ii) Relative humidity <95 percenl non condensing
d) Additional packaging and marking (limit for 30 days period)
iii) Altitude <5000 m above MSL
requirements, if any, shall be as per mutual
agreement between the purchaser and the NOTE — As a good practice it is recommended to maintain
supplier. storage temperature of O°C to + 45”C.
9.1.3 The tertiary packing of meters shall ensure 10.2.2 Storage of A4eters
protection during shipment of meters. Appropriate
measures shall be taken based on mode of transport, The meters shall be stored with packaging may be
transportation distance, quantity and type of meters and _primary or secondary packaging depending upon the
geographical location of the consignee. Some need, limitations of the storage, quantity and expected
transportation means may require specific packaging duration of storage. The stacking ofmeters should not
considerations (for example, pallet sizes, handling and exceed the specified number as mutually agreed
lifting provisions). between the purchaser and the supplier. The stacking
number should be marked on the packing and followed
9.2 Transportation of Meters by the store personnel. The cartons should .be placed
Care should be taken such that meters are not exposed according to the direction of placement of box and to
to undue shock and mishandling during transportation. allow easy accessibility with clear visibility of marking
The stacking of the package boxes inside the details. The cartons should preferably be arranged in
transporting media should be such as to avoid their free serial order of meters fcrr easy identification and
movement inside. The packing should also be protected retrieval.
from rain and dust by the transport media. Static energy meters shall not be stored for a period
more than one year in de-energized (power off)
10 INSPECTION AND STORAGE OF METERS
conditions.
10.1 Inspection on Receipt
When a meter is stored for -several months under
The inspection of received goods shall be carried out extreme ambient conditions, it is likely that RTC may
according to the sequence given in this Code. Records drift. It maybe required to adjust the time of meters if
for proof of inspection shall be maintained. This the meters are provided with time adjustment facility.
procedure will be followed over and above the standard
The maximum drift per annum permissible in the real
-goods receipt practices of the user. The meters shall be
time clock shall be as follows:
inspected to ensure that the packaging is in compliance
with 9. Additionally, it shall be verified that the Meter Accuracy Permissible Driji/Annum
documentation is commensurate with the contract and Max
that there is no evidence of physical damage due to 0.2 s * 2 min
transportation. water seepage or pilferage. Evidence 0.5 s * 5 min
of any breakage, seepage of water, etc shall be reported
to the competent authority for appropriate action. 10.3 Store Management
10.2 Storage Proper records shall be maintained and all receipt and
issue of material shall be recorded in the it. This also
10.2.1 Storage Conditions
refers to the asset management process as detailed
The meters must be stored in a clean, dry and covered in 16.
6
IS 15707:2006
10.4 Pre-instaHation Inspection for domestic, commercial and industrial purposes (see
IS 11448). The different types of meters arc as follows:
[tis the responsibility of the energy service provider to
reasonably ensure that correct meters are installed at a) Single phase direct connected meters;
consumer premises. It should be verified that the b) Three phase direct connected meters;
manufacturer’s distinctive seal is intact. Meters with c) Three phase CT connected meters; and
brokenldamaged seals ahould be returned to the
d) Three phase meters for HV supplies (CT/VT
manufacturer or sent to their authorized repair agency
connected meters).
with defect report and suitably packed to avoid damage
in transit. Such meters can be installed after repair and 11.1.2 Metering Application
restoration (including calibration), resealing and
These shall be in accordance to CEA Regulations on
submission of report by the manufacturer/authorized
installation and operation of meters.
repair agency detailing action carried out.
11.1.3 Location of the Meter (Based on Application)
A pre-installation inspection shall be carried out ifi
The location of the meter shall be in accordance to CEA
a) there is evidence of tran-sit damage;
Regulations on installation and operation of meters. In
b) more than six months have expired since the case of indoor installation at consumer premises, the
date of satisfactory acceptance inspection at focus of installation practices for tariff meter is
manufacturer’s facilities; preventing misuse and deterring tampering or bypassing
c) storage conditions of the meter are not as of meter by the consumer by having:
per 10.2.1 and the temperature of storage has
been beyond the limits of O“C to + 45°C; and a) A visually traceable and joint free incoming
cable or shrink wrapped sealed joints; and
d) meters are directly purchased by the
consumer; in which case the following shall b) Having clearly visible and accessible seals that
can be subjected to easy inspection.
be additionally verified:
1) Meters meet the requirements of this 11.1.4 Factors Affecting Measurements
Code,
There are-number of factors concerned with installation,
2) Meter is of a type, make and rating
which unless taken care of might affect the overall
approved by the energy service provider,
measurement system. These factors, particularly for 3
and
phase CT or VT connected meters are covered below.
3) ‘Meter is accompanied by its user manual These factors, for CT/VT connected meters are:
and routine test report duly certified by
the manufacturer. a) Inj7uence of VA burden — Connected burden
of both CT’s and VT’s as measured at
Records for inspection shall be maintained. terminals prior to installation. Connected
NOTE — Please also refer 10.2.2 for static meters fitted with burden should be measured and recorded and
real time clock (RTC). should match the working range of instrument
The sample size and schedule of tests shall be as transformer; and
specified in 8. For meters directly purchased by the b) Influence of CT and VT wires.
consumer, the sample size shall be 100 percent. The
In CT connected meters and CT and VT connected HV
inspection report and clearance for installation shall
meter installations the CT wire size and length, length
be done as per 8.1.
and cross-section of VT wires play a major role in
measurement accuracy. Voltage drops in VT wires
11 PUTTING INTO SERVICE
causes an error which can be as large as 1 percent or
11..1 Meter Installation Classification more in energy recording and all extra investment for
high accuracy meters and VT’s is undermined by the
While laying down meter installation practices,, it is
VT cables. Connected burden should be measured,
important to recognize that installation practices need
recorded and shall match with the working range of
to be differentiated based on classification of meter.
the instrument transformers.
These classifications are based on:
a) Meter type; 11.2 Issuance for Site Installation

b) Nature of-application; and 11.2.1 Selection of Meters
c) Location of the meter.
The meters have to be -selected based on the consumer
11.1.1 Meters are of different accuracy classes used load.
7
IS 15707:2006
11.2.2 Preparation of A4eters 750 mm and 1 800 mm. In case the meter is
provided with a secondary display unit, this
Meters have to be prepared as per the requirement of
requirement applies to the secondary display
the’ service provider and the type of installation. Such
unit only;
preparatory activities are likely to include security
, c) A minimum clearance of 50 mm should “be
sealing, record keeping, installation specific marking
and bar coding, time setting, configuration change maintained around the meter itself for better
including TOD register setting, demand period setting, inspection. This includes the space between
load survey setting, etc. two meters, between meter and the mounting
box and between two mounting boxes as the
11.2.3 Issue of Melers and Record Keeping case may be; and
The life cjcle history of meters shall be traceable from d) Additionally, for outdoor installations, the
the point of first installation. For this purpose an asset meters shall be protected by appropriate
register shall be maintained in accordance with 16.1. enclosure of level of protection 1P 55 and
Similarly, records related~o sealing should be traceable ensuring compliance with above conditions.
and maintained by the sealing management system in The enclosure should preferably be light
accordance with 16.2. coloured.
11.2.4 Packing and Transportation 11.3.2 Selection of Instrument Transformers (Where-

ever Applicable)
Meters shall be transported from the stores to the
installation site suitably with proper care so as to Reference can be drawn from IS 4201, IS 4146, IS 5547
prevent any damage or degradation of performance. and IS 11448.
During transportation, care shall be taken to protect Metering units shall use instrument transformers rated
meters from rainwater, dust and heat. The meters shall for metering use only. In no case, protection-core
be transported in their own primarylsecondary packing. instrument transformers shall be used for metering.
In case of any transportation damage, meter shall not
The primary rating of the current transformers shall
be installed and reported back to the appropriate
authority. match with the load current requirement as per the
contract demand. The secondary current and voltage
11.3 Site Preparation rating of the instrument transformers shall match with
that of the meter.
11.3.1 Selection of Site
See 5.7 of IS 11448 for guidelines on selection of
Unless specifically intended for outdoor installation, instrument transformers. However, when the meters are
metering system shall be installed indoors. The site shall provided with external instrument transformer
be accessible to the consumer as well as service compensation features, the accuracy classes of the CT/
provider’s personnel for meter reading, installation VT maybe a class lower than that recommended.
inspection and maintenance as the case may be. The
meters should not be located in inaccessible private For bulk energy transfer points, whether at consumer
areas, or areas that are unsafe, inconvenient or end or at interface points; it is recommended to use meters
unsuitable for entry by service personnel or an area with instrument transformer error compensation features
with uncontrolled or unrestrained access to animals etc. to ensure overall accuracy of the metering system.
The following shall be considered for selection of site VA rating of instrument transformers shall match the
and installation of meters: VA burden at its terminals including the burden of the
a) Metering installation shall be protected from meter. In case the actual burden presented at the
instrument transformer terminals is less than 25 percent
excessive dust and moisture, exposure to
its rated burden; additional burden shall be connected
direct sunlight, rain and water seepage and
vermin. The site temperature should be within to keep the overall burden within 25 percent to
80 percent of the rated burden.
the limits of O“C to +50”C. It should not be in
proximity of machineries, heating devices, When CT operated meters with-built in neutral current
equipment generating high vibration or measuring devices are used for the purpose uf tamper
magnetic fields and areas prone to fire and detection, the service provider shall use a -CT in the
toxic hazards; neutral circuit as well. The rating of the neutral circuit
b) Meters should not be located at an elevated CT should be identical to the CT’s on the phases.
area or a depressed area that does not have
11.3.3 Installation of Instrument Transformers
access by means of a stairway of normal rise.
The height of meter display shall be between Instrument transformer installations should be such as
8
1S 15707:2006
to ei~surc protection from tampering and maintenance bar or a terminal stud, the contact resistance shall be
of overall measurement accuracy. The following kept to a minimum and it should be ensured that the
considerations are relevant. contact area is maximum. It is preferable to use meters
with integrated CT’s so that current terminations are
11.3.3. I HV consumers up to 33 kV
not required at all. Proper bunching and systematic
All HV installations should ensure appropriate level laying of wires shall be adopted for easy identification
of safety and protection from tampering. and nmintenance. Appropriate methods shall be used
for tapping the potential signal from the circuit.
The cable terminations should be secured from
tampering by sealing, with the seals visible from 11.3.5Cabling
outside. The routing of the cables should be clearly
The size of the service cable for direct connected meters
visible and bare conductors close to termimatiom shou]d
shall be suitably selected to carry the current according
bc ]nsu]ated.
to sanctioned load as pcr relevant part of IS 3961. Based
] 1.3.3.2 LF C’0ilSUl)lf211’ on the length of the overhead cables, the galvanized
iron support wire shall be used. The service cable shall
Metering cubicles for systems using LV Current
be preferably armoured and such armour shall be
Transformers shall be manufactured as a whole unit to
earthed. For three phase 4 wire connections, usage of
incorporate both the CTS and metering unit. The
4-core cables instead of 3!A-core cables shall be
cubicles may be compartmentalized for CTS and the
preferred to reduce the possibility of burning of neutral
meter. ‘Neutral current measuring CT shall be provided
cable under highly unbalanced conditions. It is
with tmnsformcr operated LV meters having neutral
recommended to install CT operated meter above 60A
current measurement for current circuit tamper
load.
detection
Transformer operated meters shall be connected with
in case, a separate CT unit is used, the secondary cables
minimum 2.5 rnd cables. ”Higher cross-sections should
of the CTS shall be run through conduits and well
be used to ensure that the overall burden does not
protected from tampering. The CT secondary wires
exceed the rated burden of the instrument transformer
should be as short as possible to keep the burden to a
due to cabling. Appropriate colour coding shall be used
minimum. In order to avoid joints in the main cables,
for the cables appropriate to the various configurations
thread-through arrangement may be used with window
like HV 3 phase 3 wire, 3 phase 4 wire or LV
type or base mounted CTS. Alternately, meters with
connections. Metering cables should be laid in mild
thread through arrangement may be used. The window
steel pipe or conduits and there shall be no access to
size of the CTS shall be so designed as to accommodate
cables and their joints. Joints should altogether be
at least double the size of the ah.rminium conductor
eliminated in the metering conductors/cables and
cable for the maximum current rating or the CT.
service cables. Type of cable used for meter installation
In order to prevent tampering with CT cormcctions, it should be multi strand cable for flexibility and ease of
is recommended to use block CT’s that terminate handling. Single cable length should be used for source
directly on to the meter, thereby making the CT side connection. There should be no joint in the cable
secondary practically inaccessible. Alternately, thread till it is terminated on the meter. Above 50 A loads,
through meters with integrated CT’s may be used. In flexible copper cable shall be used for termination on
case of non-thread through type of CT units (bar type the meter.
or bus bar type), where CT units need to be inserted in
11.3.6 Terminations
series with the load cable, the cable shall be terminated
properly at both ends of the bus bar with proper lugs. a) Appropriate crimping device shall be used for
crimping the lugs. Thimbles shall be of
11.3.4 Distribution Transformer Metering appropriate configuration (pin type, fork type,
Distribution transformer metering systems should be etc) to match with the terminal block for low
mounted at safe heights making unauthorized access current connection. For high current
difficult. It is recommended to use meters with wireless terminations, crimping shall be used with
communication for this purpose. Metering units shall cable crimping tools, and multiple point
be designed to use minimum number of joints in the crimping shall be done for the lugs used for
load circuit. The secondary cables of the CTS shall run higher current ratings;
through conduits and well protected from damage or b) If the terminal block is of MS cage clamp type,
weathering. It shalI be ensured that the CT secondary there is no need to use any lugs and the copper
conductors are not unnecessarily long and over- cables shall be directly terminated at the
burdening the CT. Wherever lugs are bolted to the bus- clamp;
9
1S 15707:2006
c) The recommended tightening torque must be earthing shall have continuous connection with the
exerted on the screw to ensure proper tightening earthing pit of the transformer. The service provider shall
of the terminations. It is recommended to use maintain the earth resistance as prescribed in IS 3043.
proper tools, equipments for this purpose;
MV and HV consumers shall additionally provide
d) Usage of lugs as per the recommendation of earthing connection from a local earthing pit as per
manufacturer and ensuring proper crimping standard practices and guidelines. Multiple earthing,
will protect the joints from failures; grid earthing or single point earthing maybe provided
e) For high current terminations, tensile test and based on the supply system and fault level.
shock test shall ‘be performed after crimping
the lugs; The earthing connection shall not be used as return
conductor and shall not carry neutral current. The
fl Where, aluminium cable termination is to be
consumer earth and supply neutral should not be
done on copper bus bars or brass studs,
connected in the consumer premises after the metering
hi-metallic type of lugs shall be used;
point.
.!3) Copper cables shall be used for the direct
NOTES
connected meters;
1 There is a tendency to use water supply pipe line or exposed
h) For indoor meters, the wiring shall be done iron structure as earthing terminal. This shall be strictly avoided
such that the cables enter the meter box from and no electrical circuit shall be connected to these metallic
the bottom or rear side. This prevents the structures.
service cable from tampers etc; 2 All the earth terminals of appliances, equipment, machines
etc, shall be terminated to the consumer earthing paint only,
j) Use of test terminal block (TTB) is not
3 Lightening strip shall not be used as earthing terminal.
recommended for LV metering. However they
shall be used for HV metering; and 11.3.9 Meter Wiring and Connections
k) Bi-metallic lugs shall be used wherever
The service provide shall provide phase(s), neutral and
required.
earth connection to the consumers. The service provider
11.3.7 Mounting of Meters shall provide separate neutral to each consumer up to
the metering point and same shall be used by the
Meters should be mounted such that they can not be
consumer. Wherever there is multiple meter
easily dismounted and the wiring termination is not
installations, busbar arrangement shall be used for
accessible without breaking a seal.
neutral, so that looping is avoided.
Additionally, special care should be taken to ensure
The neutral shall be used for carrying return current
that the electromechanical meters are mounted within
only. The neutral of one consumer shall not be
+0.5° of the gravitational vertical using the triangular
connected to other consumers who have independent
mounting arrangement i.e. one hanging hole at the top
and separate supply comection. The consumer shall
and two fixing hole on the opposite side of the terminal
ensure all the correct wiring practices m-e followed and
block provided on the meter. Further, according to
neutral is not looped with another consumer or meters
footprints size/triangular mounting arrangement
in the same premises. Consumer shall not earth the
available for various make of meters a template for
neutral after the metering point.
footprints should be prepared to mm-k position of
correct hole for installing the meter vertical. The Relevant Indian Standards may be referred for wiring
template should made of a heavy metal plate in such a diagrams for meters.
way that verticality is ensured by its own weight. The
template should be hanged on the top screw so that it 11.3.9.1 Supply side wiring
can take normal vertical position for marking correct
The supply side wiring is the responsibility of the
holes. Multiple meter footprints can be marked on the
service provider and following shall be ensured:
same metal plate. Alternately a plumb bob (to mark a
vertical line prior to installation) or spirit level (on the a) Supply wires provided are of suitable rating
top horizontal surface of meter to accurately identify as per the relevant part of IS 396 I;
the bottom fixing hole position) can be used for the b) When a number of meters are connected to a
purpose of installation. single distributing mains for registering
electricity supplied to different consumer
11.3.8 Installation Site Earthing
loads, separate service lines — phase(s) and
The energy service provider shall provide the earthing neutral, shall be used for each meter. Each
connection to the consumer in accordance to the Indian independently metered consumer load must
Electricity Rules, 1956 at the metering point. The be directly connected to distributing mains
10
IS 15707:2006
through its meter connected in specified phase a) Phase association;

sequence so as to meet accuracy requirements b) CT polarity;
of this Code; c) VT polarity;
c) Supply wire shall be properly terminated; d) Phase angles;
d) Connection shall be as per connection diagram e) Phase sequence;
mentioned on meter as per relevant metering
~ System conditions and abnormal conditions
standard;
such as unbalanced capacitors; and
e) Service provider shall use its own earthing for
g) Actual CT/VT ratio (for transformer operated
its devices; and
meters).
o Utility shall ensure that the capacitor used for
power factor shall be used with proper filter To achieve error free wiring, appropriate colour coding
circuit to avoid generation of harmonics. of wires shall be adopted.
11.3.9.2 Consumer side wiring The static meter should support instantaneous
parameters capture by a measuring device through
The consumer shall ensure proper wiring and shall get
optical reading of the meters and the phasor diagram
this wiring certified from a competent authority such as
so obtained by reading the instantaneous parameters
a licensed electrical contractor. It shall be ensured that:
shall be verified at site for the above errors.
a) Proper safety norms as per IS 732 are followed;
11.5 Commissioning of Meters and Reporting
b) Wiring system is capable of handling the
consumer load; a) After any metering installation activity, a
c) .Suitable protection devices such as MCB/ report shall be made by energy service
Isolator/Fuse are used at the point of supply provider and consumer or his representative
after the meter. Earth leakage protective shall verify the report;
devices are installed in accordance with the b) The report shall have all detail about new/old
Indian Electricity Rules; and meter, sealing detail etc;
d) Provision of proper earthing for household c) If noticed, energy service provider shall
appliances. inform consumer about any abnormal wiring
The wiring is totally isolated and not shared with other at consumer end;
premises. Interconnection of phases or neutrals of loads d) Any floating neutral condition if noticed by
connected to different meters are not permitted. the consumer should be brought to the notice
of the energy service provider and same shall
Consumer shall undertake to get any alteration in the
be resolved by the energy service provider;
connected Ioad, wiring and protection system verified
and
for its appropriateness by a competent authority. Energy
service provider shall ensure that the capacitor for e) Checks for phase-to-phase, phase to neutral
improvement of power factor when used shall be with up to the consumer main switch shall be
proper filter circuit to avoid generation of harmonics. carried out by energy service provider before
It shall be maintained properly and according to the switching on the load.
load and need of improvement of the power factor.
11.6 Security Sealing
11.3.10 Guideline for Choice of Tamper ProofMeter Box Following sealing shall be ensured at time of meter
installation:
The meters should preferably be mounted in suitable
enclosure and shall be sealed at multiple points. The a) Manufacturer’s meter seal;
meters shall be mounted within specified permissible b) Service provider’s meter seal;
inclination as specified in relevant 1S. There shall be
c) Terminal cover seal;
no access to the meters without breaking the sealing
d) TTB seals (where applicable);
arrangement (see IS 14772). Window shall be provided
in the box to see the meter reading. e) CT-VT seals;
t) Meter box seal; and
11.4 Meter Connections
g) Sealing on cable joint box, etc.
11.4.1 Verification of Connections
There should beat least one seal at all point mentioned
Following should be verified after installation of the above (wherever applicable). The seal shall be tamper
metering system: proof. The consumer shall be briefed about seals.
11
“IS 15707:2006
The seals shall be distinctive and follow the seal 12.3 Accuracy Requirements
management system as per 16.2.
12.3.1 Under Reference Conditions
12 MAINTAINING IN-SERVICE Limits of error specified in Table 2 are applicable for
12.1 In-service Testing in-service meters when tested under reference
conditions.
Metrological testing and functional verifications are
carried out on meters in service as per requirement of 12.3.2 On-site Conditions
relevant Indian standards:
Limits of error stated in Table 3 are applicable when
a) on receipt of consumer’s complaint or internal in-service meters are tested on-site under specified
report; and operating conditions.
b) as part of in-service compliance inspection.
12.4 In-service Compliance Testing
Methodology for in-service testing is as per 12.7.
It is att economical method of monitoring and
12.2 Methods of Testing determining whether a population of meters, installed
in-service for a number of years without attendance,
12.2.0 Meter testing can be carried out on-site or at a
is continuing to operate in accordance with metrological
meter test station, provided the test facility adopted
specifications and other fictional requirements. It is
complies with IS/ISO/IEC 17025. All test equipment
also to assign a performance indicator to the
shall be traceable to the National Standards. Meter for
population so that appropriate asset -management
LV installation maybe tested including CTS to get the
decisions can be taken. The -results of in-service
overall accuracy of the meter. Meter and CT/PT for
compliance testing shall be noted in the asset
HV installation shall be tested separately.
management register.
12.2.1 On-site testing may be carried out:
12.4.1 Initial Life/Compliance Period
a) under prevailing load, taking care that the load
and power factor satisfy the range as indicated The initial life is determined in the design stage or
in Table 3; in the prototype stage. This is done either from
b) by injection method after connecting a suitable prediction of reliability y from manufacturers’ data of
phantom load or external load. For reactive reliability of components submitted at the time of
measurement, the test will be performed only type approval or from accelerated life testing of a
by this method; and prototype.
c) by installing off-line check meter — The meter If the initial life of a population is not certified for want
of at least same or better accuracy class shall of data or absence of a notified body, the meter service
be installed for minimum one billing cycle. provider in the best interest of own asset management
There shall be sufficient increment in the and the consumers, carries out initial in-service
energy register to ensure the accuracy is better compliance testing after completion of two years in
than 1/10 of the accuracy of the meter if the service so as to take care of any initial instability of
error is found to be more than the Iimits as performance. Generally, it is done in the 3rd year and
specified in the Table 3. the compliance period is reckoned from the initial year
On site testing of CTs and PT’s shall be carried of service.
out using either by comparison with standard
instrument transformers or by simulation 12.4.2 On-going Compliance
techniques using appropriate test equipment.
After expiry of the initial life of meters of a particular
The connected burden shall be measured and
type, it may be extended on the basis of test data
recorded and shall be verified to ensure that
collected from meters in the field or normally removed
it is commensurate with the rated burden of
meters. The life is thus continuously monitored and it
the instrument transformer.
may be increased or decreased periodically depending
NOTE — For reactive measurement, on-site accurzcy
on the data.
test shall be by the injection test method using phantom
load kit. In the absence of such data or the notified body, the
meter service provider shall carry out on-going in-
12.2.2 Main, Check and Standby Meters
service compliance tests after expiry of the initial
These shall be in accordance with CEA (Installation compliance period, so as to assign a new compliance
and Operation of Meters) Regulations. period.
12
IS 15707:2006
Table 2 In-service Limits of Errors and Uncertainties of Meter Test Equipment

(Clause 12.3.1)
sl Accuracy Type of Connection Test Points P.F. Overall Uncertainty of Limits of

No. Class Meter Test Equipment Error
Percent Percent
(1) (2) (3) (4) (5) (6) (7)
i) 2.0 Direct connectecVWith CTS 10 percent 1~to IM,,X 1.0 *0.4 *2,0
0.5 lag +0.6 +2.0
0.8 lead +0,6 +2.0
ii) 1,0/1.0s Direct Connected/For CTS 5 percent Ib to 1~,,. 1.0 *0.4 *l, o
10 percent fb 0.5 lag *0,6 X1.o
i O percent f~ 0.8 lead +0.6 *1. O
iii) 0,5s For CT/VTs 5 percent Ib to fM,i. 1.0 +(). 1 +0.5

10 percent f~ to [~,,1 0.5 lag *0.12 +0,6
10 percent f~ to [~,,, 0.8 lead *0,12 *0,6
NOTE — cos Us/sin Q applicable for active/reactwe energy respectively.
Table 3 In-service Maximum Permissible Errors and Uncertainties of

Meter Test Equipment
{Clause 12.3.2)
sl Accnracy Test Points P.F. Overall Uncertainty-of Meter Maximum Permissible

No. Class Test Equipment (M.T.E.) Error (M.P.E.)
Percent Percent
(1) (2) (3) (4) (5) (6)
O 2.0 10percent 1~to [w, 1.0 and 0.5 lag +0,6. *3.()
ii) 1.0 10 percent Ib to t~u 1.0 and 0.5 lag +0.4 *2.5
iii) 1.0s 5 percent 1~to [~,, 1.0 and 0.5 lag *0.3 f2,0
iv) 0.5s 5 percent Ib to I~u 1.0 and 0.5 lag *0.2 rl.o
NOTE— cos @/sin0 applicablefor active/reactive energy respectively.
12.5 In-service Compliance — Installation components and wires with respect to its
Verification — Irrstaliaticm Audits application, meter enclosure authenticity of
sealing system — both verification and
Installation audit is a periodic examination of the
security seals, type of enclosure used, number
metering system installation to assess the health of the
of seals used, whether number of seals is
system and to ensure continued health of the same. All
justified etc.
meter installations need to be periodically audited under
asurveillance plan. The energy service provider shall audit the installations
on a periodic basis. Periodicity of the audit shall be
Various aspects to be observed during the audit are:
defined as per the revenue potential of the metering
a) Physical examination of the installation, its health system (that is, for high value consumers, it should be
in general and factors related to good installation more frequent than to that of a domestic consumer).
practices like neatness of installation, mounting For LV direct connected consumers suitable statistical
method, dressing of cables, colour coding of plan may be employed.
wires, ferruling including following common
nomenclature in ferrules, integrity of the 12.6 Implementation of Compliance Requirements
installation and its proneness to tampering, This Code -will be notified by appropriate authority for
observations on safety aspects like bare implementation.
connections, naked joints, earthing etc; and
12.6.1 Existing Meters
b) Detailed examination related to electrical
nature like, correctness of connections, The existing meters will be deemed to have the initial
appropriateness of metering system in-service compliance period as indicated in Table 4.
13
IS 15707:2006
Table 4 -Deemed Initial Compliance Period of standard random number generation table. Damaged/
Meters In-service.(During Implementation) tampered meters are to be excluded from the
(Clause 12.6.1) population selected.
In case a population fails on the basis of single

s] Accuracy Deemed Initial Compliance
No. Class Period (Years) sampling, additional samples may be taken to arrive at
(1) (2) (3) ‘
conclusions on the basis of corresponding double
samples as given in Table 3A of IS 2500 (Part 1).
i) 2.0 s 10
ii) 1.0/1.0 s 8 If any on site test shows that the meter is outside the
iii) 0.5 s 5 permissible error limits, investigation shall be made to
determine if it is due to .effe.ct of influence quantities or
A population ofmcters which have outlived the deemed the installation. The meter shall be tested in the
initial compliance period, will bc tested for on-going laboratory and decision is to be based on results of
compliance within 3 years from the year of laboratory testing,
implementation of this Code.
Samples, if tested in a laboratory and found satisfactory,
A population of meters which is within the deemed will be put back in service after evaluation.
initial compliance period, will be tested for on-going
in-service compliance within 1 year from the year of 12.7.5 Evaluation
expiry of the deemed initial compliance period.
Testing will be done on site or under reference
12.6.2 New Meters conditions to determine:
A population of new-meters of any type will undergo a) Non-registration with voltage alone;
compliance testing in the third year after being placed b) Meter constant;
into service, in order to determine the initial in-service c) Specific functional criteria;
compliance period effective from the year of
d) Metrological test points (minimum three);
installations.
e) Compliance period will be determined on the
12.7 Methodology of In-service Compliance basis of one of the methods to be selected by
a meter service provider for its area of
Metrological characteristics and functional
operation;
performance of meters under compliance requirements
are tested. It is generally done on the basis of a sampling f) Non-compliant population of meters will be
plan, with a selected no of test points and functional removed from service within the period
characteristics. indicated in Table 5 or Table 6; and
g) However, to arrive at the final decision for
12.7.1 Sampling Plan such a population, second sampling may be
carried out as per Table 3A of IS 2500 (Part 1)
12.7.2 Single sampling by attributes on the basis of
and overall passlfail decisions may be taken
normal distribution is adopted in the present Code.
according y.
12.7.3 Population
12.7.5.1 Variable error-band nlethod (constant
Meters arc to be grouped in a population based on: AQL)
a) Manufacturer; Table 5 gives accuracy class wise different initial and

b) Type; on-going compliance periods to be assigned on the basis
c) Year of installation; of variable error-bands at fixed AQL.
d) Geographic area; 12.7.5.2 Variable AQL method (constant error-band)

e) Overhead/7Jnderground service;
Table 6 gives accuracy class wise different initial and
f) Indoor/Outdoor installation; on-going compliance periods to be assigned on the basis
@ Whether repaired; and of variable AQL for class-index error-bands.
h) Any other appropriate characteristic.
12.8 Meter Test Equipment (M. T.E.) Standards and
.12.7.4 Selection of Samples and Pass/Fail Criteria Periodicity of Calibration
Tables 1 and 2A given in “IS 2500 (Part 1) will For the purpose of dependable and effective calibration
determine selection of samples and pass/fail criteria. and metrological verification by a meter service
Samples are to be selected at random on the basis of provider, the latter will properly maintain calibrated
14
..-.,.. “,...-.., .-- —-—- . ..-. . . . . . . ..—
1S 15707:2006
Table 5 Initial and On-going Compliance Period of Meters In-service

(After Implementation by Fixed AQL Method)
(Clauses 12.7.5 and 12.7.5.1)
SI Accuracy Error-Bands in Class Index In-service Compliance Period (Years)

No. Class Load and RF. Range / - -
Initial (AQL = I) On-going (AQL -4)
(1) (2) (3) (4) (5)
i) 2.0 *2.O 10 5
ii) *2.5 7 4
iii) +3.0 4 2
iv) *4.O To remove within 2 years To remove within 2 years
v) 1.0/1.0 s *1.O 8 4
vi) +1.5 5 3
vii) +2.0 3 2
viii) +3.0 To remove within 2 yews To remove within 2 years
ix) 0.5s *0.5 6 3
x) +0.75 4 2
xi) +1.0 2 1
xii) *1.5 To remove within 1 year To remove within 1 year
Table 6 Initial and On-going Compliance Period of Meters In-service

(After Implementation by Fixed Error Band Method)
(Clauses 12.7.5 and 12.7.5.2)
s! Accuracy AQL for the Class Index In-service Compliance Period (Years)
No. Class Error Band / — -
Initial Ongoing
(1) (2) (3) (4) (5)
i) 2.0 1.0 10
ii) 2.5 7 5
iii) 4.0 4 4
iv) 6.5 To remove within 2 years 2
v) 10 — To remove within 2 years
vi) 1.0/1.0 s 1.0 8
vii) 2.5 5 4
viii) 4.0 3 3
ix) 6.5 To remove within 2 years 2
x) 10 To remove within 2 years
xi) 0.5s 1.0 6
xii) 2.5 4 3
xiii) 4.0 2 2
xiv) 6.5 To remove within I year 1
xv) 10 To remove within 1 year
standards in its meter testing station. The accuracy class be partially complying to its specification, the use of
of meter test equipment shall be as follows: the working standard shall be restricted to working
range and class only. When a working standard is
Accuracy Class of Accuracy Class of Meter calibrated and is found to be outside its specification,
Meter Under Test Test Equipment its use shall be immediately stopped. The reason shall
(1) (2] be investigated and the occurrence reported within 3
2.0 s 0.3 working days of its discovery. Notification shall be
1.0/1.0 s 0.2 given of the details and results of the investigation. The
0.5 s 0.1 result of the investigation shows:
a) Whether metering equipment calibrated or

Various standards and their periodicity of calibration
tested using that working standard since its
are shown in Table 7.
last satisfactory calibration complies with the
When a working standard is calibrated and is found to relevant standard document; and
15
IS 15707:2006
Table7 Periodicity of Calibration of Various Standards ofa Meter Test Station

(Clause 12.8)
sl Energy Standards (Maintained in M.T.S.) Calibration Interval (Months) Remarks

No. A
/ \
Normal Extended
(1) (2) (3) (4) (5)
i) Reference standard (External calibration only) 24 Stability to be monitored

ii) ac/dc transfer standard (External calibration) 24 60 Depending on stability
iii) ac/dc transfer standard (In-house calibration) Prior to use 6 Depending on stability
iv) ac transfer standard (When used in-house) 2 6 Depending on stability
v) ac transferstandard(Whenused on-site) Before and after use —
vi) Working standard (Optional external calibration) 12 —
vii) Working standard (In-house calibration) 2 6 Depending on stabi lity
b) The reason why that working standard is Table 5 or Table 6 for on-going compliance
outside its specification. requirements.
i) Location — It does not require the
15 DI-SPOSAL
Standards of any meter operator agent to
be maintained or used at anyone location, Meters shall be systematically disposed off at the end
and of their useful life, on obsolescence or when declared
2) Mobility — Reference standards and acl irreparable/uneconomical to repair during its service
dc transfer standards shall not be mobile life. Such meters shall be scrapped and disposed off
standards and shall remain in one location taking care that no part is left in re-usable or recyclable
as far as possible and only be moved for form. It shall be ensured that meter identification plates/
verification at an accredited laboratory. labels are destroyed and recorded into the asset
NOTE — ac transfer standards and working management system. Special disposal actions, as
standards may be mobile standards. applicable, shall be adopted for hazardous material/
components like lithium batteries, magnets, lead
13 REPAIR
containing parts, etc.
At the end of useful life considering all the extensions,
or at the end of in-service compliance period, a meter 16 ASSET AND SEAL MANAGEMENT”SYSTEM
is removed. The next action is either refurbishment/ 16.1 Asset Management
repair in a workshop belonging to the service provider,
manufacturer or a third party. Otherwise it may be An asset management system shall be maintained for
disposed off. keeping records in order to ensure that the life cycle
history of meters is traceable from the point of first
The decision taken is centered on economical installation. The details of the consumer number/
considerations involving: consumer name and address against which the meters
a) Remaining useful life after repair; are issued shall be maintained in the stores and the
meters shall only be issued against the consumer
b) Cost of repair; and
number/consumer name issued from the stores.
c) Asset disposal value.
The register shall contain information on meter serial
14 RE-CERTI-FICATION/RE-VERIFICATION/ number, energy service provider assigned serial
IN+ERVICE RE-COMPLIANCE number, procurement reference (for example, purchase
After refurbishment/repair of meters removed from order number), sealing details, manufacturer’s name,
service, it is required as a good practice that these are: year of manufacture, type of meter, meter constant,
accuracy class, current rating, installation site reference
a) Re-certified by the notified body for the and date of installation, test results or reference to test
remaining portion of useful life; results(accuracy test, dial test), initial reading,
b) Re-verified by the notified body and the seals information about auxiliary~quipment Iike CT/VT and
applied; and their ratings. The asset register should preferably be in
c) Inspected for in-service re-compliance testing electronic form with features of traceability of the
and re-compliance period determined as per history of the metering installation.
16
1S 15707:2006
Status of initial and on-going compliance should be c) Seals when removed, leave detectable evidence;
indicated in the register with reference to test data of d) Procurement, stocking, issue, installation and
the samples. disposal of seals is traceable;
Records of returned meter are also to be maintained. e) Traceability should be uniquely identifiable
All the details of old meters are to be entered in the to a responsible individual;
register when the old meter comes to the store. f) All numbered seals are traceable to consumers
through meter numbers;
16.2 Seal Management g) Seals are secured against misuse;
The energy service provider shall maintain an h) Sealing punch, when used shall be uniquely
appropriate seal management system. The seal identifiable and traceable; and
management system ensures that seals are secure, j) Seal Management system itself is secure with
controlled, uniquely identified and traceable. proper access control.
A seal management system shall ensure the following: All numbered seals should be traceable to consumers
through meter numbers. All broken seals shall be
a) Seals are unique and distinctive for each disposed off taking care that the seals are destroyed so
manufacturer/energy service provider; that they cannot be re-used. Proper records of such
b) Seals are not easily imitable; disposal shall be maintained.
17
.. . . .. . . .
Bureau of Indian Standards
BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote
harmonious development of the activities of standardization, marking and quality certification of goods
and attending to connected matters in the country.
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implementing the standard, of necessary details, such as symbols and sizes, type or grade designations.
Enquiries relating to copyright be addressed to the Director (Publications), BIS.
Review of Indian Standards
Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed
periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are
needed; if the review indicates that changes are needed, it is taken Mp for revision. Users of Indian Standards
should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of
‘BIS Catalogue’ and ‘Standards : Monthly Additions’.
This Indian Standard has been developed from Doc : No. ET 13 (5659).
Amendments Issued Since Publication
Amend No. Date of Issue Text Affected
BUREAU OF “INDIAN STANDARDS
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Regional Offices : Telephone
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Printed at Rabhat Offset Press, New Dethi-;

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Free Standard provided by BIS via BSB Edge Private Limited to Galaxy Test & (Reaffirmed

November 2006 Price Group 8

a) Electricity consumers — set requirement targets;

1 SCOPE a) Correct and proper installations;

1S No. Title definitions-shall apply, besides the definitions given

3 TERMINOLOGY NOTE — Unless the life is extended by the notified body

3.30 Asset Register — A registration system, 4.2 Validity of Approval

3.31 Accredited Laboratory — The laboratory for 4.3 Amendment

c) Drawing of nameplate; 5.2 Existing Type of Meters

a) Meter type; 11.2 Issuance for Site Installation

11.2.4 Packing and Transportation 11.3.2 Selection of Instrument Transformers (Where-

through its meter connected in specified phase a) Phase association;

Table 2 In-service Limits of Errors and Uncertainties of Meter Test Equipment

sl Accuracy Type of Connection Test Points P.F. Overall Uncertainty of Limits of

iii) 0,5s For CT/VTs 5 percent Ib to fM,i. 1.0 +(). 1 +0.5

NOTE — cos Us/sin Q applicable for active/reactwe energy respectively.

Table 3 In-service Maximum Permissible Errors and Uncertainties of

sl Accnracy Test Points P.F. Overall Uncertainty-of Meter Maximum Permissible

NOTE— cos @/sin0 applicablefor active/reactive energy respectively.

In case a population fails on the basis of single

a) Manufacturer; Table 5 gives accuracy class wise different initial and

d) Geographic area; 12.7.5.2 Variable AQL method (constant error-band)

Table 5 Initial and On-going Compliance Period of Meters In-service

SI Accuracy Error-Bands in Class Index In-service Compliance Period (Years)

Table 6 Initial and On-going Compliance Period of Meters In-service

a) Whether metering equipment calibrated or

Table7 Periodicity of Calibration of Various Standards ofa Meter Test Station

sl Energy Standards (Maintained in M.T.S.) Calibration Interval (Months) Remarks

i) Reference standard (External calibration only) 24 Stability to be monitored

Bureau of Indian Standards

Review of Indian Standards

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

BUREAU OF “INDIAN STANDARDS

Regional Offices : Telephone

Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg 23237617

Southern : C.I.T. Campus, IV Cross Road, CHENNAI 600113 22541216,22541442

Printed at Rabhat Offset Press, New Dethi-;

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